He had nowhere to flee and had no choice but to surrender.
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遁 is a classical/literary character. In modern standard Chinese, 逃跑 (táopǎo) or 逃脱 (táotuō) are the everyday equivalents. 遁 appears mainly in idioms (遁形 = to vanish, 遁世 = to withdraw from the world) and literary or historical writing.
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遁 contains 辶 (movement radical) + 盾 (shield). Picture hiding behind a shield and slipping away — fleeing under cover.