I mean think about it.. When someone is stressed and is in a position of power, they will never admit their feeling of insecurity. Instead, they'll try to control their inferiors and prove their seniority. How? Either by speaking loudly and quickly so that no one else can be heard, or by proposing strict measures for the rest of you, or even by making you feel insecure for yourself by using personal remarks.
Whenever someone pulls that on you, think again! This can't be coming from a relaxed person.. This person is probably trying to prove their worth to somebody else and this stresses the hell out of them. They probably don't have a clue what they're doing and are striving to impress.
Give them the time to relax and breathe deeply. The stress you feel when being close to such a person, isn't yours; it's the reflection of their emotional turbulence onto you. Realize it and never fall for their trap ever again! :)