Alternatively, being unable to whisper to someone screaming and throwing shit at you... Get a spray bottle with water in it. Like for plants, or a misbehaving cat... Get your running shoes on first though... Squirt them. They will chase you. Run. They can burn off their manic energy and clam down. Then employ the whisper technique. Apologize for squirting them, don't try and rationalize to them why you did it (it's important not to invite back their prior headspace; saying something like "because you were acting crazy" will just bring back all those emotions). Just say "I'm sorry". If they are calm enough you can softly ask them "are you okay?" Body language is important, a gentle touch on the shoulder communicates you're there for them (positive touch) while negating the water bottle attack (negative touch). (This is also a good test to determine what the reason for their episode was. If they are disgusted or pull away violently after being touched my first guess would be there's some physical/emotional trauma like rape or molestation. Many people are not be able to talk about it at all and the bottling of that intense emotion would certainly cause a manic episode.) They now have an opportunity to communicate. Offer them items of comfort. Blanket, tea, water(careful they may want revenge) sweets, etc...