It's not like playing for survival is inherently bad, although in this case I fail to see how India could draw with so much time left, but in general, committing to either cause tends to work. What tends to tear a team apart is the point of confusion. The bigger the task, the earlier doubt casts a pall over the innings. Bad scores from the top order in a long chase worry the rest of the batting, but a good opening partnership strengthens confidence. When the batsmen is not sure whether scoring or surviving is the best option, that is when the wickets come fast.
There should be minimal threat of that right now for India, but confident batsmen still get out. One wicket probably won't ruin this for India, but two in succession might have them scrambling and trying to work out who is going to be there at the end. England will have to do quite a bit of damage to have India in real despair and by the time that damage is done, it would hardly matter how India feel about it. Of course, the masterstroke for England is that India will continue to offer shots throughout the innings. The game shall hang in the balance for long enough that wickets should come if they do things right.
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