Canto 3 -
Araṇya-kāṇḍa
Chapter 19: Khara Sends Fourteen Rākṣasas to Destroy Rāma
Text 3.19.19

तस्याश्चानृजुवृत्तायास्तयोश्च हतयोरहम्।
सफेनं पातुमिच्छामि रुधिरं रणमूर्धनि॥

tasyāś cānṛju-vṛttāyās tayoś ca hatayor aham
sa-phenaṁ pātum icchāmi rudhiraṁ raṇa-mūrdhani

tasyāḥ = [the blood] of that woman; ca = and; anṛju-vṛttāyāḥ = of deceitful behavior; tayoḥ ca = of Those two [brothers]; hatayoḥ = when They are killed; aham = I; sa-phenam = the foamy; pātum = to drink; icchāmi = want; rudhiram = blood; raṇa-mūrdhani = at the forefront of a battle.

I want to drink the foamy blood of Those two [brothers] when They are killed at the forefront of a battle and [the blood] of that woman of deceitful behavior.

It is understood from this verse that Śūrpaṇakhā thought that Śrī Rāma and Śrī Lakṣmaṇa deformed her upon being impelled [to do so] by Sītā-devī.

It is not appropriate to interpret this verse as meaning, “I want to drink the foamy blood of Those two [brothers] and that lady of deceitful behavior when the three of them are killed in the front of a battle” because there is no possibility that Sītā-devī would ever go on the frontlines of a war.1

Because Śūrpaṇakhā really wanted this to happen, she repeats it in the following verse.

1 Rāmāyaṇa-bhūṣaṇa: sītāyā raṇa-mūrdhani gamanāsambhavād dhatāyā iti viparināmo na yuktaḥ. anyathā aśakyatvād raṇa-mūrdhanīty uktam