If you are already saved to a raid but still want loot from it... Have a warlock summon you inside but don't accept the summon till the boss is about to die. This will give you 2 minutes to accept the summon and 1 minute before you get hearthed out.
Possibly on a fight you have on farm you could have a warlock and 2 others stay out of combat and summon when he is almost dead if it is a longer than 3 minute fight.