IRL, being anywhere near a tank cannon's barrel when it fires can be lethal. Heck, plenty of people have been killed or seriously injured by the backwash from "bazooka" types of portable rocket launchers.
Its important to realize those injuries stem from two entirely different forces. Injuries from "bazooka" type weapons typically stem from plumes of extremely hot, high velocity exhaust gases. Whereas injuries from standing near artillery typically comes from what is known as "over pressure".
Contrary to most perceptions of explosives, over pressure is what kills the majority of people. Secondary injuries stem from shrapnel. Over pressure typically causes internal injuries which can range from crushed inner ears to crushed lungs and bladders.
The reason I make these distinctions is because hand held weapons are specifically designed to limit overpressure. Otherwise, firing the weapon would place an expiration date on its users. Though firing such weapons from enclosed spaces can still be extremely lethal to all within the confined space.
Notice the Javilin in this video has two rocket motors. The first charge launches but is so short it prevents both exhaust burns and over pressure. http://www.youtube.com/watch?v=Sg3UXzseLTI
Once clear of the launcher, the secondary motor kicks in to carry the missile to its target.