It's possible to do it at part throttle. It's called "floating the gears" and you need to have a VERY good understanding about matching the RPM's between tranny and engine to do it without causing harm.
DOing it at WOT will be next to impossible. First of all, the design of the T-5 prevents you from pulling it out of gear under load. The dog teeth are designed to lock together and only unlock when there is no load on the tranny (clutch pushed in, or RPM's in sync w. no load). At WOT, you'll prob need two hands to pull it out of gear.