Surrender can be the goal for some people's BDSM. Surrender is the giving in to the experience or the giving in to what's being done to you by your partner. This can be very different to the endurance which some people (e.g., pain sluts) look to achieve in activities such as pain play.
While for some it might seem that struggle and resistance are obvious reactions to being tied up or being repeatedly whacked or flogged, for people seeking surrender the fight may give way to a complete yielding to the intensity of the experience and allow their internal barriers to fall. In particular, the use of pain in BDSM is often precisely for the purpose of compelling surrender to allow the consequences of the pain to freely occur.
During BDSM play there may be a phase of either resistance or endurance before surrender occurs (if it does at all). This can happen because of fear, or because of a strong desire or need not to lose control, or because of uncertain trust about your partner or about your own potential reactions, or for other reasons. As the scene progresses the actions of your partner, your own responses to what's happening (e.g., the pain or the restraint), your developing confidence in the way the scene is playing out, or your own unleashed need to yield, all combine and may overwhelm the barriers opposing surrender. At this point surrender will occur and instead of resisting, enduring, or merely submitting, you embrace it all and become part of it and it becomes part of you.
Some people experience this surrender as a form of subspace, some as a feeling of complete liberation, some as the metaphorical being one with the Universe, and other reactions. Often it is a very liberating experience (despite that it might be occurring while you're tied up and can't physically move).
With experience the phases of resistance, uncertainty, and endurance become shorter or even non-existent.