Legal implications of this prank going horribly wrong?

Question

I remembered coming across this comic from Saturday Morning Breakfast Cereal.

In this comic, Tommy replaces his boss' gun with a fake that just shoots out a "Bang!" flag. Later, he breaks into his office and pretends to be a robber, presumably expecting his boss to try to defend himself with the fake gun. However, his boss committed suicide, and happened to use the fake gun.

Assume the following:

• Tommy did not steal the real gun, he hid it elsewhere in his boss' office.
• Tommy has a job where he could plausibly need access to his boss' office (maybe an IT guy or something), so he has a key.
• Tommy did not intend to actually hurt his boss.
• Tommy's boss' suicide was entirely intentional, and he would've died even if Tommy had never attempted the prank.
• There was no suicide note.
• State and country doesn't actually matter, because I'm curious as to how different systems might handle such a strange situation.

My questions are as follows:

1. Is Tommy guilty of any crime?
2. If his boss didn't commit suicide, and tried to defend himself against the "robber" as planned, would Tommy be guilty of a crime even if ultimately no one was actually hurt?
3. If a real robber had broken into the boss' office before Tommy had a chance to play his prank, and the boss was unable to defend himself as a result, what charges would Tommy be facing?
4. Could his boss sue him if the scenarios in (2) or (3) came to pass?

Answer 1

In Canada, I think Tommy would be found guilty of criminal negligence causing death.

Criminal negligence

219 (1) Every one is criminally negligent who
(a) in doing anything, or
(b) in omitting to do anything that it is his duty to do,
shows wanton or reckless disregard for the lives or safety of other persons.

(2) For the purposes of this section, duty means a duty imposed by law.

Causing death by criminal negligence

220 Every person who by criminal negligence causes death to another person is guilty of an indictable offence and liable

(a) where a firearm is used in the commission of the offence, to imprisonment for life and to a minimum punishment of imprisonment for a term of four years; and
(b) in any other case, to imprisonment for life.

Tommy didn't show any consideration for the safety of his boss, and even though he didn't directly kill him, he showed disregard for him. The fright Tommy caused his boss eventually caused his death (had Tommy been a real robber, he could've been charged with first-degree murder).

2. Probably not: if nothing happens, then it will probably be taken as a good ol' prank.

3. Probably be charged with criminal negligence, assuming that Tommy took no action to assist his boss after realizing the situation.

4. This would likely be a civil case, rather than a criminal one. I'm not too familiar with civil law, but I wouldn't be surprised if assault came into play.