Can tress end her leg hydraulic movement on a figure and then immediately use a strain for a MP and use that mp to exit the space?

No.

Move by X spaces must end movement first. You can't combine movement from move X spaces (which happens immediately when the ability says) and moving by spending movement points (which is a during-your-activation ability and thus can only be performed when not resolving other abilities).

Further question....X spaces is different from movement points, right?

So if she got two surge she could move through a hostile figure and the the open space beyond?

7 minutes ago, Zrob314 said:

Further question....X spaces is different from movement points, right?

Yes. See Move X Spaces - no extra movement point costs. You have to do that immediately, you can't save move X spaces for later.